For over a century to date, physicians and surgeons have created and clinically utilized an ever increasing range and diversity of artificially-created therapeutic appliances as an effective means of repair and treatment for patients. When considered in historical perspective, such therapeutic appliances have been primarily developed and most intensively used by medical practitioners in orthopedics, radiology, surgery, and cardiology; and typically may be broadly divided into two separate and distinct general categories of prostheses (or prosthetic devices) and physiological-assist articles or apparatus. It will be recognized and appreciated, however, that due to the disparity of approach and medical assessment as well as the specific medical needs of an individual human patient, the different medical areas of orthopedics, radiology, surgery, and cardiology have generated a variety of diverse constructions, structures, and innovations in therapeutic appliances which meet the singular requirements of that medical specialty.
For example, orthopedics, being concerned with a correction of skeletal deformities, have concentrated heavily if not exclusively on the creation of prostheses which serve as a complete substitute and artificial replacement for a missing part of the human skeleton. Thus, orthopedic prostheses include structural devices such as a plate in the skull; a graft replacement for a bone; a synthetic patella (or kneecap); and a surgical nail or spike by which to anchor a ligament, or tendor, a bone to a bone. Similarly, other prosthetic devices include mechanical joint or flow connectors such as a hip or shoulder joint replacement, and a prosthetic hearing aid.
In comparison, the therapeutic appliances generated and developed by the departments of radiology and cardiology have been frequently physiological-assist articles rather than prosthetic devices as such. As used herein, a physiological-assist article or apparatus does not serve as a substitute or replacement part for a missing or destroyed organ, structure, or tissue in the living body. Rather, a physiological-assist article is an auxiliary construction and structure which is surgically positioned or implanted into the living body of the patient in order to maintain, control, or additionally regulate the existing organs and tissues of the body; and serves as an aid in the performance of their intended function during life. Physiological-assist articles are thus supplemental, often incremental, and frequently duplicative therapeutic constructions and structures which aid, abet, and help to supply what is needed in a secondary, adjunct, or subordinate role to accomplish a medical result, objective, or end. Thus, physiological-assist articles are not themselves prostheses in that they do not and cannot serve as a complete substitute for or replacement of a missing or destroyed organ, tissue, or body structure.
Some of the most commonly known and utilized physiological-assist articles are cardiovascular or gastrointestinal devices; and these generally may be segregated and distinguished into not less than four distinct groups, which are: (a) structural assist devices which are exemplified by stents used for treating obstructive or abnormally dilated lesions (aneurysms) involving blood vessels, bile ducts, ureters and the gastrointestinal tract; (b) mechanical flow assist articles such as blood filter devices positioned in the major blood vessels for collecting clots; (c) electrical assist articles such as cardiac pacemakers positioned in the ventricle or atrium or both of the heart; and finally, (d) electro-mechanical articles such as cardiac assist devices including temporary or permanent artificial heart chambers, ventricular assist pumps and drives, and artificial heart stimulators. All of these may be properly considered as physiological-assist articles rather than prostheses.
In addition, there are a number of proper or true prosthetic devices originating from the radiology and cardiology departments. Representative of these today are synthetic blood vessels intended as complete substitutes and/or replacements for specific sections of arteries or veins. Similarly, the ongoing development and use of an artificial heart as a partial or complete substitute and replacement for a defective native heart is today a rapidly developing and ongoing area of major research for prostheses. It will be recognized and appreciated that these specific instances and examples are; merely illustrative and representative of the range and diversity of articles and devices commonly known and used as therapeutic appliances for the human patient today.
Given the range, variety, and diversity of therapeutic appliances available as well as in frequent usage today as surgically implanted or positioned articles and devices within the human body, the greatest danger and fear of the patient is that the implanted therapeutic appliance might break, fracture, or rupture at an indefinite time in the future. Thus, if the electrical lead of a cardiac pacemaker previously imbedded into the heart wall fractures or ruptures; or if a flange of a heart valve cracks; or if an intravascular stent in a blood vessel begins to fragment; or if the prosthesis of the bone becomes partially or completely detached, there is typically only one recourse left to both the physician/surgeon and the afflicted human patient--a complete surgical excision of the defective structure and a replacement with a new, substitute device.
To be sure, this course of remedial surgery is not undertaken lightly or casually; and the risk to the patient from a complete surgical excision operation with a subsequent complete replacement of the defective device can be a very hazardous and extremely dangerous procedure. The reasons for this high risk and extreme danger are twofold: First, the surgical excision procedure actually destroys a portion of the existing normal tissue surrounding the flawed appliance as a consequence of surgically excising the flawed device from the position in which it has been implanted previously. Such surgical excision almost always causes some nerve and/or vascular tissue loss as well as some structural bone and/or muscle loss in the local area surrounding the therapeutic appliance within the body. Thus, surgical removal of the flawed appliance surgically must cause some tissue destruction and some permanent loss of function or support even when the new substitute appliance is implanted. Second, it is most common for those who are of poor medical condition, or are of advancing age, or are physically frail to be persons which typically require the in-vivo positioning or implantation of a therapeutic appliance in the first instance. Thus, it is typically persons with poor or troublesome heart conditions which require the placement of cardiac pacemakers; and it is usually those persons afflicted with an aneurysm which require stent as a therapeutic appliance; and it is commonly the person who has suffered a fracture of bone who requires a bone prosthesis to replace the now destroyed original bone. Thus, all of these persons are medically disadvantaged in the original circumstances which required the surgical positioning of a therapeutic appliance in order that their medical condition be improved and their health enhanced. Such people incur a very high risk and hazard from such surgical excision procedures and the inherent dangers of such intensive surgery using generalized anesthesia for a prolonged time. For the extremely frail, the very aged, and the medically unfit, the choice sometimes reduces itself to a single question: Is it to be a death by waiting for the flawed therapeutic appliance to fail completely such that the natural life function can no longer be sustained; or a death on the surgical operating table at a chosen time and place due to the inability of the patient to tolerate the surgical excision and appliance replacement procedure!
It will be recognized and appreciated, therefore, that there has been a long standing and continuing need for a meaningful alternative to surgical excision and therapeutic appliance replacement as the sole remedy available to date. While some patients are properly fit candidates for the surgical excision and replacement procedure, a great proportion of humans having therapeutic appliances implanted within their bodies cannot risk the hazards of such radial surgery. For such persons, their choices are few or none. Accordingly, were an in-vivo method for repairing a ruptured segment of a therapeutic appliance already surgically positioned within the body of a living human to become available, such an in-vivo repair method would be an outstanding achievement, be an immeasurable benefit, and be a meaningful alternative to the predicted dire consequences of submitting to a surgical excision and replacement procedure.